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    Red and Painful Eye – Unilateral and Bilateral (Diagnosis and Treatment)

    Ears, Eyes, Nose, and Throat

    Last Updated Dec 29, 2022
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    First 5 Minutes

    • Critical not to miss sight-threatening conditions such as acute angle-closure glaucoma, endophthalmitis, scleritis, uveitis, iritis, keratitis.


    • Conjunctivitis is characterized by inflammation of the conjunctiva and dilatation of the superficial conjunctival blood vessels, resulting in hyperemia (red or pink appearing eye) and edema of the conjunctiva (1).
    • For this summary, a patient with a red or pink eye refers to conjunctival and/or scleral redness.
    • The differential diagnosis is wide and ranges from benign presentations (subconjunctival hemorrhage) to sight threatening conditions (acute angle-closure glaucoma)
    • Table 1 summarizes the key causes for red eye, which can be narrowed down by acuity, presence of pain, and laterality (1,2).

    Diagnostic Process

    • Narrowing down the diagnosis of red and painful eye involves a thorough history and ophthalmologic examination with the following elements:
      • Visual acuity.
      • Penlight examination.
      • Intraocular pressure.
      • Skin and lid examination.
      • Slit lamp examination.
      • Fluorescein examination.
    • The diagnostic process and treatments for vision-threatening and common causes of red and painful eye are outlined below.


    Criteria For Hospital Admission

    • Dependent on assessment by ophthalmology.
    • For sight-threatening conditions, hospital admission may be warranted if there is inability to adhere to treatment (e.g., medication compliance, social marginalization, housing insecurity, barriers to seeing ophthalmologist, etc.)

    Criteria For Transfer To Another Facility

    • Dependent on local guidelines. In general, transfer may be considered if:
      • Patient care requirements exceed hospital capabilities (e.g., cardiac monitoring, intensive care, pediatric or maternal care, etc.).
      • Treatment is not available and cannot be delivered to current facility.
      • Specialist consultations are required and not available at current facility.

    Criteria For Close Observation And/or Consult

    • Emergent ophthalmological consultation indicated for patients with suspected acute angle-closure glaucoma, endophthalmitis, scleritis, uveitis, iritis, keratitis.

    Quality Of Evidence?


    • There is a wide range of studies and systematic reviews with small variation between studies. However, some of the studies are as old as 20 years.

    Related Information

    Reference List

    1. Leibowitz HM. The red eye. N Engl J Med. 2000;343(5):345-351. doi:10.1056/NEJM200008033430507

    2. Azari AA, Barney NP. Conjunctivitis: a systematic review of diagnosis and treatment [published correction appears in JAMA. 2014 Jan 1;311(1):95. Dosage error in article text]. JAMA. 2013;310(16):1721-1729. doi:10.1001/jama.2013.280318

    3. Frings A, Geerling G, Schargus M. Red Eye: A Guide for Non-specialists. Dtsch Arztebl Int. 2017 Apr 28;114(17):302-312. doi: 10.3238/arztebl.2017.0302

    4. Gilani CJ, Yang A, Yonkers M, Boysen-Osborn M. Differentiating Urgent and Emergent Causes of Acute Red Eye for the Emergency Physician. West J Emerg Med. 2017 Apr;18(3):509-517. doi: 10.5811/westjem.2016.12.31798.

    5. Thomas PA, Geraldine P. Infectious keratitis. Curr Opin Infect Dis. 2007;20(2):129–41.

    6. Bourcier T, Thomas F, Borderie V, et al. Bacterial keratitis: predisposing factors, clinical and microbiological review of 300 cases. Br J Ophthalmol. 2003;87(7):834–8.

    7. Rothova A, Buitenhuis HJ, Meenken C et al. Uveitis and systemic disease. Br J Ophthalmol. 1992;76(3):137.

    8. Radosavljevic A, Agarwal M, Chee SP, Zierhut M. Epidemiology of Viral Induced Anterior Uveitis. Ocul Immunol Inflamm. 2022;30(2):297-309. doi:10.1080/09273948.2020.1853177

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